1. Field of the Invention
This invention relates to hammer mills and in particular to heavy duty mills of the type employed to break up discarded automobile bodies. Hammer mills or shredders of this type are large enough to receive an entire automobile body and of sufficent power to reduce it to fragments or pieces for subsequent separation into various categories of materials to be recycled.
2. Description of the Prior Art
Hammer mills of the type herein described conventionally include a rotor which serves to mount a series of pivoting hammers. The automobile bodies or other items to be shredded are conveyed to the vicinity of the rotor and the impact of the pivoting hammers on the items results in shredding them. Because of the nature of the items being shredded, the hammers after a time will wear and become less effective in the shredding operation. In many prior art systems of this type the hammer must then be replaced which can be a time consuming operation considering the mass and weight of the hammer units. In some prior art systems, there is provided double headed hammers so that when one head wears the hammer is reversed and remounted to bring the other head into operation. In order to do this, it is necessary to shutdown the hammer mill so that the hammers can be dismounted and remounted with the opposite head in operative position.
Examples of hammer mills of the general type in which the present invention is used are disclosed in U.S. Pat. Nos. 1,041,495 and 3,727,848. Further, a double headed hammer of the type found in the prior art is disclosed in U.S. Pat. No. 5,002,233.
A basic disadvantage of prior art systems in which double headed hammers are used is that the mill must be shut down in order for the hammers to be remounted with their unworn heads in operative position. The downtime, of course, results in the expense of a major machine being nonused for substantial periods. It is to this general problem that the present invention is directed.